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Old April 30th 06, 06:05 AM posted to rec.radio.amateur.antenna
Cecil Moore
 
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Default A little more on missing degrees

Reg Edwards wrote:
If Line-1 has impedance Zo1 and is a fractional wavelength L1 long,

and Line-2 has impedance Zo2 and is a fractional wavelength L2 long,

then when both lines are connected together and are brought into
so-called 1/4-wave resonance by pruning the length of one of the
lines, it is IMPOSSIBLE for L1 + L2 to equal 1/4-wavelength or 90
degrees.


If we have three sections and Z02 Z01,

---Z01---+---Z02---+---Z01---

the first impedance discontinuity causes a phase
shift in the *opposite* direction from the second
impedance discontinuity. That's why moving a loading
coil from a base-loaded position to a center-loaded
position requires more degrees of coil.

W8JI has been trying to make a big deal out of that
fact but it is just simple physics.
--
73, Cecil http://www.qsl.net/w5dxp